Different standard keyboard arrangements are known. The most widely used English-language alphabetic key arrangement is the QWERTY arrangement. Other types of standard English-language alphabetic key arrangements include the QWERTZ arrangement, the AZERTY arrangement, and the DVORAK arrangement. Each of these arrangements, when presented as a full-size keyboard, utilizes 26 keys for 26 different characters.
Numeric characters are often presented along with alphabetic characters on keyboards of communication devices, such as telephones. One standard setting body, the International Telecommunications Union (“ITU”), has established phone standards for the arrangement of alphanumeric keys. One such standard, shown in FIG. 1, corresponds to ITU Standard E.161, entitled “Arrangement of Digits, Letters, and Symbols on Telephones and Other Devices That Can Be Used for Gaining Access to a Telephone Network” (also known as ANSI TI.703-1995/1999 and ISO/IEC 9995-8:1994). According to this standard, ten keys are used to present the alphabetic characters A-Z and the numbers 0-9. In order to enter alphabetic characters, the user may be required to multi-tap the keys until the desired character appears on a display screen, among other known entry techniques.
Mobile communication devices that include a combined text-entry keyboard and a telephony keyboard are known. Examples of such mobile communication devices include mobile stations, cellular telephones, wireless personal digital assistants (PDAs), two-way paging devices, and others. Combining a traditional-style text-entry keyboard (e.g., a QWERTY-style keyboard) with a traditional-style telephony keyboard on the same mobile communication device typically involves undesirable ergonomic and/or intuitive user interface compromises. The size of the keyboard is often limited by the size of the device, making the keyboard more difficult to use.
One prior art device that incorporates a combined alphabetic/numeric keyboard is the RIM Blackberry 950 mobile communication device, shown in FIG. 2. In this device, numeric characters share keys with alphabetic characters on the top row of the QWERTY keyboard. Another prior art device that incorporates a combined alphabetic/numeric keyboard is the RIM Blackberry 6210 mobile communication device, shown in FIG. 3. This device utilizes numeric characters in a numeric phone key arrangement consistent with the ITU Standard E.161, discussed above. The numeric characters share keys with alphabetic characters on the left side of the keyboard. Both of these devices are designed for entry of characters using the thumbs.